13. Women of childbearing age who are pregnant or plan to become pregnant. NOTE: women of childbearing potential with an uncertain pregnancy status must have a negative pregnancy test within 7 days prior to enrollment. Pregnancy tests are required as part of standard routing clinical practice at all centers whenever female patients are exposed to x-ray radiation. Since this protocol does not require any exposure of the female patients to x-ray and x-ray exposure is part of the clinical procedure, it is the responsibility of the investigators to ensure that pregnant females will not be exposed to x-ray at any time